Section III. SIGNAL SOURCE RF HEAD TROUBLESHOOTING
consists of a series of steps. Each step lists the control
3-14. Scope
position or operation for the test equipment, the control
a.
The paragraphs in this section help to determine
position or operation for the rf head under test, the
which of the circuits in a defective rf head is at fault, and
normal indication or condition,
and the corrective
to localize the fault in the circuit to the defective
measures to be taken if the normal indication is not
component. Some faults, such as burned-out resistors
obtained. Supplementary information in the form of
or broken or bent connector pins, often can be located
microwave and electrical schematic diagrams,
with
by smell or sight. The majority of faults, however, must
parts lists, for each rf head are presented with each test
be localized by checking meter indications, voltages,
chart. Definitions of the schematic symbols used are
resistances and waveforms. The troubleshooting charts,
given in the schematic circuit symbols table in chapter 1
schematic diagrams, parts lists, and unit resistance
of TM 9-4931-294-15/1. The replaceable parts lists
charts for the rf heads are supplied as an aid in localizing
augment the schematic diagrams by presenting a
malfunctions. The troubleshooting procedures tabulated
detailed description of the electrical and microwave
below are to be followed if the results of the operational
components of the rf heads.
checks indicate a defect within one of, the rf heads of
a Preliminary Procedure. Set up the equipment
the signal source.
as shown in the figure illustrating the setup for signal
b. The BWO power supply and
source leveling in chapter 2, section II, of TM 9-4931-
the tunable synchronizer are not covered in this
294-15/1, utilizing the rf head which is to be tested.
section and are considered to be operating properly.
b.Troubleshooting Procedure. After performing
When the results of the operational checks indicate the
the preliminary procedure described in a above, proceed
need for troubleshooting these units, refer to the
with the steps of the test chart applicable to the rf head
commercial manuals covering these units.
to be tested, using the pertinent schematic diagram and
parts list.
3-15. Rf Head Troubleshooting
Troubleshooting of the rf heads is accomplished with the
use of test charts. Each chart
Change 1 3-33
